MULTIPATH
Section: Linux Administrator's Manual (8)
Updated: July 2006
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NAME
multipath - Device mapper target autoconfig
SYNOPSIS
multipath
[-v verbosity]
[-d]
[-h|-l|-ll|-f|-F]
[-p failover|multibus|group_by_serial|group_by_prio|group_by_node_name]
[device]
DESCRIPTION
multipath
is used to detect multiple paths to devices for fail-over or performance reasons and coalesces them
OPTIONS
- -v level
-
verbosity, print all paths and multipaths
-
- 0
-
no output
- 1
-
print the created or updated multipath names only, for use to feed other tools like kpartx
- 2 +
-
print all info : detected paths, coalesced paths (ie multipaths) and device maps
- -h
-
print usage text
- -d
-
dry run, do not create or update devmaps
- -l
-
show the current multipath topology from information fetched in sysfs and the device mapper
- -ll
-
show the current multipath topology from all available information (sysfs, the device mapper, path checkers ...)
- -f
-
flush a multipath device map specified as parameter, if unused
- -F
-
flush all unused multipath device maps
- -p policy
-
force maps to specified policy:
-
- failover
-
1 path per priority group
- multibus
-
all paths in 1 priority group
- group_by_serial
-
1 priority group per serial
- group_by_prio
-
1 priority group per priority value. Priorities are determined by callout programs specified as a global, per-controller or per-multipath option in the configuration file
- group_by_node_name
-
1 priority group per target node name. Target node names are fetched in /sys/class/fc_transport/target*/node_name.
- device
-
update only the devmap the path pointed by
device
is in.
device
is in the /dev/sdb (as shown by udev in the $DEVNAME variable) or major:minor format.
device
may alternatively be a multipath mapname
SEE ALSO
udev(8),
dmsetup(8)
hotplug(8)
AUTHORS
multipath
was developed by Christophe Varoqui, <christophe.varoqui@free.fr> and others.